Is there any point going to GP?

I have a sore shoulder, I don't know what caused it, it just started and it's been hurting since early July. I can raise it normally directly in front of me, provided it's not bearing any weight, but anything slightly to the side and I can't get my hand above waist height without pain. It makes changing gear in the car uncomfortable and opening the garage door impossible.

What can/will a GP do if I take it to him? I've had a couple of sessions physio, which were expensive, but haven't helped

When I had a knee problem, that GP wrongly diagnosed, after 18 months I went back and he referred me to an orthopedic specialist, who tested me manually and said it was cartilidge, and referred me for an MRI scan , where it was confirmed and its extent. As it has worsened since July, and you have such limited mobility, you should go to Doc, who probably will refer you to a specialist

I'd definitely go and see your GP, you shouldn't be in pain for so long. I strained my neck and upper arm and was in agony despite painkillers and heat pads. He gave me something stronger for the pain and to help me relax and referred me to the in-house physiotherapist who was able to give me exercises.